Vacuum Line Fix

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Feb 7, 2012 | 04:49 PM

Blitzcraig

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Joined: Feb 2012

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From: Chaplin, Ky

Vacuum Line Fix

My 93 F350 blows cold air to the floor and defroster. I found a missing vacuum line that supposed to go to the switch thing on top of the blower housing. It's a tiny white vacuum line that had been broken off. The only place I could find this stuff that everyone said was hard plastic was at a Mercedes-Benz dealer. So I went to a junk yard and found some but it was very brittle just like the remnant on the truck so I cut a length from inside the cab where it was still nice and pliable. I cut back the remaining line well into the harness and found that it was pliable inside the protective covering. I spliced it together with heat shrink tubing and now all is well and warm in the cab. I think people think that is hard plastic when really it has become very brittle over time.

Feb 8, 2012 | 06:41 AM

mistakenID

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Joined: Jul 2004

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From: West Valley Utah

You can also splice those spaghetti lines with small, rubber vacuum hose. Make sure it's a tight fit. Makes it easy to route lines to other locations and sharper bends that old lines won't take.

Last edited by mistakenID; Feb 8, 2012 at 06:41 AM. Reason: spelling

Feb 8, 2012 | 02:22 PM

Blitzcraig

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Joined: Feb 2012

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From: Chaplin, Ky

Update: the vacuum hose I fixed seems to activate the switch only when Max A/C is selected. Turns out I'm still getting cold air when on defrost or floor. Any ideas?

Feb 8, 2012 | 06:21 PM

tecgod13

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Joined: Sep 2007

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From: Western Mass

Keep looking under the dash for the hose running to the blend door. What you fixed was the door that sucks in new air, or recirculates the cab air (for max cooling effect).

I don't know what its like in a 93, but my 88 its cake to pull the glove compartment and get access to the heater core. Mine adjusts the temp with a regular wire, your year maybe different. Also wouldn't hurt to pop open the heater core access panel and clean things out there. Sometimes crap falls in from the dash vents and can block the blend door partially open.